1. Field of the Invention
The invention relates to a fuel delivery system arrangement for connecting an electric operated fuel injector between a fuel rail and an air intake of a spark-ignited, internal combustion engine.
2. Discussion of Related Art
Spark-ignited, fuel-injected internal combustion engines are often used in automotive vehicles. Fuel is injected into an intake system of such an engine by electric operated fuel injectors of a fuel rail (sometimes referred to as a fuel manifold) assembled to the engine.
Targeted types of fuel injectors inject fuel into the vehicle engine in a direction, or directions, that are other than along the fuel injector axial centerline. A split stream fuel injector is an example of a targeted fuel injector. When a targeted fuel injector is used in an engine, the fuel injector has to have a particular angular or circumferential orientation about its centerline so that the direction(s) of fuel injection will be properly targeted. Improperly targeted fuel injectors may derogate engine performance and/or compliance with applicable vehicle emission requirements.
Proper targeting of a fuel injector typically requires a proper axial positioning of the fuel injector. This is typically achieved by positioning the fuel injector nozzle, which contains one or more metering orifices from which fuel is injected into an engine, in a fixed geometric relation to a socket receptacle of the engine intake system into which the nozzle is inserted in a sealed manner. When a fuel rail containing fuel injectors that have been properly circumferentially located in respective outlet cups of the fuel rail is assembled to an engine that has injector-receiving socket receptacles, the act of inserting the nozzles into properly sealed relationship with the socket receptacles can complete proper targeting of the fuel injectors. The achievement of the correct circumferential location of the fuel injector to the fuel rail outlet cup is referred to as “clocking” the fuel injector.
A fuel rail may comprise attachment features, aperture brackets for example, with which threaded fasteners are associated to fasten the fuel rail to an engine. Once the fuel injector nozzles have seated in properly targeted positions in the socket receptacles, a need for further tightening of such fasteners in order to secure the fuel rail to the engine may induce undesired stress, distortion and/or movement. For example, if fuel injector nozzles have been seated in properly targeted positions in respective socket receptacles in engine air  intake manifold runners before the fuel rail attachment fasteners have been fully torqued, the fuel rail may distort in some way, and/or there may be some relative movement between some component parts, as the fasteners are finally tightened to full installation torque. With prevailing manufacturing methods and dimensional tolerances of manufactured parts, it seems that the possibility of such distortion, or movement of component parts, at time of fuel rail assembly to an engine, cannot be totally foreclosed in all circumstances.
It has been known to mechanically retain a fuel injector in a fuel rail outlet cup by a retention clip that constrains the two against any substantial movement, both circumferentially and axially. A fuel rail that incorporates such a capability may improve serviceability should it become necessary to remove the fuel rail from an engine and thereafter reattach it.
Due to the enhanced stringency of vehicle emission requirements and the use of four valve cylinder heads with two intake ports, it is now more important than ever to insure the fuel injectors are properly clocked. Therefore the requirements that fuel injectors be properly clocked when inadvertently twisted during assembly or maintenance operations are greater than that previously required. Many prior fuel delivery system arrangements retain the fuel injector to the cup with a double C-type clamp clip. The double C-type clamp clip has a primary C clamp which engages an arcuate slot of the injector body. The primary C clamp retains the injector body in a generally axial direction. A secondary C clamp is typically provided which extends generally perpendicular from the primary C clamp. The secondary C clamp typically has slots or projections which interact with a flange portion of an outlet cup to make it a click-on type connection. The secondary C clamp will typically have a contact surface to prevent rotation of the fuel injector body with respect to the fuel injector outlet other than its desired angular position. An example of such a clip is shown in U.S. Pat. No. 5,040,512.
There has been a tendency from many of the prior clips to lose their retention with the fuel injector body when the fuel injector is inadvertently twisted during a maintenance operation or during a misassembly.
It is desirable to provide an improved fuel delivery system wherein the clip is less susceptible to being splayed open whenever a fuel injector is torqued inadvertently.